I have used Seamonkey since Netscape. I like having browser, mail agent, even html composer all together. RSS is not so much something I do, but I've been doing more of it, lately. What I like is that I just click on a feed link that interests me, like your
feed.php, and I am shown the following page. When I click to subscribe, the group is immediately created under Blogs & News Feeds of Seamonkey mail and the last 10 posts of the feed are downloaded there. That's pretty cool.